1. Most MP3 frequencies are 44100HZ. The code rates are 128, 192 and so on.

2. The frequency mentioned here is the sampling rate, which is generally 44100KHz, because this is the standard for music CDs. ?

Each song is ripped from a CD, converted into a WAV file, and then converted to MP3 using software such as Lame.

3. So it must be a sampling rate of 44100KHz. Unless yours is not a song, but you recorded it yourself as a WAV file, and selected another sampling rate when recording. ?

4. The main factor that affects MP3 sound quality is the bit rate. The best ones now are 320K CBR (fixed bit rate) and VBR (variable bit rate). VBR files are a little smaller than CBR. 192K VBR is the most popular on the Internet, and can meet the requirements of sound quality and file size at the same time

Finally, I would like to remind you: MP3 transcoding is distorted, and this distortion cannot be reversed. In other words, if you convert MP3 to WAV sound quality, the file size will increase dozens of times, but the sound quality will still be the same as MP3. ?

5. If you want to listen to low distortion, it is better to listen to CD or download APE